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Numerical Modeling of Periodical Structures
Nešpor, Dušan ; Bartušek, Karel (referee) ; Brančík, Lubomír (referee) ; Fiala, Pavel (advisor)
The thesis discusses the dynamic electromagnetic field on periodic structures. The author focuses on three principal types of resonant structures, considering their application possibilities. In general, these types can be individually defined as follows: materials exhibiting a negative refractive index of the incident electromagnetic wave; structures with gradual changes in impedance, characterised by their usability as reflectionless surfaces; and periodic structures able to conveniently shape the magnetic field distribution. Materials of the third group within the above-shown short list facilitate the fabrication of magnetoinductive lenses for nuclear magnetic resonance. The presented analysis of the properties of periodic resonant structures is mainly based on numerical models utilising the finite element method, and this approach is combined with both the derivation of the corresponding analytical relations and an experimental measurement of the non-radiating component of the electromagnetic field. The thesis includes a physical description of the basic elements of periodic resonant structures. Physical properties of the elements were examined in detail via numerical analysis. In the course of the research, the data acquired through this analysis and the related experimental measurement enabled the author to propose a method for optimising the most widely used resonant structures. Moreover, several new versions of resonant elements, structures, and fabrication techniques were also designed. The results obtained from the numerical analyses carried out to examine the central physical properties of the fabricated structure samples were all verified via the designed method for measuring the non-radiating component of the magnetic field.
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Static load test and the assessment ceiling of reinforced concrete structure built in the 1st half of 20th century
Málek, Jaroslav ; Láník, Jaromír (referee) ; Žítt, Petr (advisor)
This master thesis deals with static load test and static assessment of selected segments of reinforced concrete ceiling construction of the Hennebique system at the Faculty of Arts at Masaryk University in Brno. This thesis contains: the execution of the static load test, the data evaluation of the static load test and the data evaluation of the complementary laboratory testing, geometric orientation of bearing elements, the checking of the ceiling placement in the peripheral position, and the diagnosis of the reinforcing of the construction. This thesis also includes the static assessment according to various standard norm rules and the numerical analysis in ATENA software program.
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Stone columns - importance of arch effect
Vanko, Peter ; Zdražil, Karel (referee) ; Miča, Lumír (advisor)
The aim of the the thesis is to study the development of arch effect depending on the change of the various parameters such as grid of columns, height of embankments, material of embankment fill and material of columns. The first phase of work summarizes theoretical knowledges of stone columns and arch effect. The next phase deals with analysis of the effect of arch using numerical modeling. In the next part of the second phase circular tank based on stone columns will be modeled, where deformations and stress on columns will be monitored in changing constitutive model and applying substitute characteristics. Obtained results will be evaluated in conclusion.
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Design of excavation for reconstruction of shopping centre
Červenka, Jan ; Miča, Lumír (referee) ; Chalmovský, Juraj (advisor)
The thesis is divided into three parts. In the first one it deals with the design and the assessment of the once-anchored soldier pile wall, which provides an excavation for the reconstruction of the shopping centre Prior in Zlín. The retaining structure is designed according to the limit state method, using the GEO5 software and the Excel spreadsheet editor. In the second part, the thesis deals with the price comparison of the classic version of the soldier pile wall with soldier pile, IPN profiles, with over one-pole anchorage with the help of the buckle, with the variant with larger spread, where the soldier pile from the pair of UPN profiles are adapted for anchoring. The third part solves the problem of the distribution of a lateral ground pressures along the length of the soldier pile wall. For comparison with the empirical methods of design of lagging, the results of normal pressure from the mathematical model, solved by the numerical analysis, the finite element method, were used in the Plaxis 3D program. Hardening soil model was used as the material model.
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Design of excavation in the Brno city centre
Kováč, Vladimír ; Miča, Lumír (referee) ; Chalmovský, Juraj (advisor)
The work deals with the problem of the ultimate and serviceability limit state of a once-anchored retaining structure of an excavation on Krenova street in Brno. The calculation of the ultimate limit state is solved manually and provides an input into the serviceability limit state, which is solved by means of a numerical analysis using a finite element method. To calculate the serviceability limit state, these constitutive models: Mohr-Columb, Hardening soil and Hardening soil small strain model are used.
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Numerical Analysis of Influence of Electromagnetic Fields on Small Airplanes
Řezníček, Zdeněk ; Hazdra,, Pavel (referee) ; Karban,, Pavel (referee) ; Raida, Zbyněk (advisor)
This thesis deals with numerical analyses of electromagnetic fields on small aircraft with composite parts as an innovative way for assessment of their inherent protection against electromagnetic effects of outside environment in all development stages. It is concentrated for procedures of creation of geometrically and materially complex models for simulating calculations in the time as well as frequency domains, execution of the simulations itself and comparisons of results between the internal electromagnetic calculations and executed experimental tests. Achieved results were verified on a simplified reference model of aircraft's fuselage and two aircraft prototypes VUT100 and EV-55 of the company Evektor, spol. s r. o.
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Determination of input parameters of advanced soil constitutive models using optimization methods
Koudela, Pavel ; Miča, Lumír (referee) ; Chalmovský, Juraj (advisor)
Choice of the constitutive model and determination of input parameters are necessary for a successful application of numerical methods in geotechnical engineering. Higher complexity of modern constitutive models results in an increase of the number of input parameters and time requirements for their calibration. Optimization methods are a possible solution for this problem. An application in which metaheuristic optimization method Particle swarm optimization (PSO) is involved is presented in this thesis. Critical review and testing of various PSO alternatives was performed in the first part of this thesis. The most efective PSO alternatives were chosen. In the second part connection between PSO algorithm and finite element solver was prepared. Automatization of determination of constitutive models input parameters was performed on three boundary value problems: laboratory test (oedometer), in-situ test (pressuremeter) and geotechical construction (retaining wall). Three types of constitutive models are used. Linear elastic-perfectly plastic Mohr-Coulomb model, elastoplastic non-linear Hardening soil model and Hardening soil - small strain model.
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Experimental and Numerical Analysis of the Volume Changes of Fine-grained Concretes
Odstrčil, Štěpán ; Frantík, Petr (referee) ; Kucharczyková, Barbara (advisor)
This diploma thesis deals with the experimental and numerical analysis of volume changes of fine-grained concrete. Experiments were carried out, measuring both the length changes as well as the mass losses and the internal temperature of the test specimens made from fine-grained concrete. The measurements were divided into two parts (phases). The first phase took approx. 72 hours. The second phase was focused on the long-term measurements and will be completed after stabilization of the mass losses and length changes. In the diploma thesis, the first phase of measurement was elaborated in detail, both in terms of experimental and numerical analysis. In addition, a C # .NET program was created to facilitate the processing of raw measurement data from the data logger. Finally, a comparative calculation was performed according to the model B4, where the result of the calculation was compared with the results of the experiment.
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Hygrothermal processes in walls of wooden houses
Vencel, Lukáš ; Vlach, František (referee) ; Bečkovský, David (advisor)
This diploma thesis solves the problems of hydrothermal processes in walls of wooden houses and associated issues. A chosen were two apartment buildings, where they underwent exmerimental measurement of indor air, in order to determine the boundary conditions commonly boundary building evelope. Was followed by hygrothermal analysis of four commonly used constructions of wooden buildings in the Czech Republic, using various numerical methods. The quantity of information obtained from various numerical methods were analyzed individually. The final part of the thesis is devoted to experimental measurements of diffusion properties of materials. Namely foil vapor barrier, in terms of its influence on the perforation vapor diffusion resistance factor. Information obtained from the experiments were applied to re numerical analysis for walls with a foil vapor barrier. Followed by comparing both cases, in terms of changes hygrothermal behavior of structures with influence of perforation of the vapor barrier.
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